The larynx and primary function In order to survive, the body is equipped with certain programmes of primary functioning. The larynx's primary function is to protect our airways, stopping saliva and food particles from getting into the lungs. Essentially the larynx is a sphincter mechanism. The larynx also has a secondary function, which is to act as a pressure valve. By closing off the airway, the larynx enables us to strain, give birth and vomit. The pressure valve also enables us to clear the lungs when we need to cough.